Question

PLEASE HELP? Problem on geometric series, file attached below.

Answer 1

I don't know how I would set this up.

Answer 2

@hartnn

Answer 3

@whpalmer4

Answer 4

@anonymous_user

Answer 5

My question here is how I'd find r?

Answer 6

a5 = a1*r^4
so r^4=81
r=+-3

Answer 7

because a GP goes on like a,ar,ar^2,ar^3,ar^4.........

Answer 8

r=+-3? That doesn't make sense...

Answer 9

@sidsiddhartha

Answer 10

Nevermind, I got it! Thanks!

Answer 11

Since the S5 < a5 ro r=-3

Answer 12

u check ur ans like that
a1=4,
a2=4*(-3)=-12;
a3=(-12)*(-3)=+36,
a4=36*(-3)=-108
a5=(-108)*(-3)=+324
so total sum
a1+a2+a3+a4+a5=4-12+36-108+324=244
it is equal to s5 given

Answer 13

did u get it? @grungeandcake33